The present invention relates to a lancer for withdrawing a sample of blood from a patient via a lancet. More particularly, the invention is drawn to a lancer for obtaining blood samples from alternate sites, i.e., an arm, leg, or sites other than the fingertip, for the purpose of measuring the concentration of an analyte in blood, i.e., glucose.
Conventional lancers on the market are designed to sample blood to determine an analyte in blood such as glucose. These conventional lancers use a finger blood-sampling approach which can be quite painful for the patient because of the concentration of nerves that are present on fingertips. Some companies are developing lancer technology to obtain blood samples from sites other than fingertips (xe2x80x9calternate sitesxe2x80x9d). Such alternate sites include arms and legs which have a smaller concentration of nerves thus resulting in less pain being associated with the blood sampling process. However, the problem with these alternate sites in that they do not bleed as easily or as well as sites on the finger when pierced using fine gauge lancets. Therefore, there is the need for a new lancer mechanism that can obtain sufficient blood samples from these alternate sites.
The present invention is drawn to an improved lancer having features that increase the capability of drawing blood from alternate sites. The present invention forces or milks blood from the lancet puncture on an alternate site by using a twisting motion to act as the mechanism to force blood from the alternate site. During operation, the user activates the lancer to create a lancet puncture in the alternate site, i.e., arm or leg. Once a puncture is created, the user twists the device approximately xc2xc of a rotation while the alternate site tip is against the patient""s skin. The user maintains the twisting force for several seconds while fingers, crenellations (castle-like features) or trapezoid features on the alternate site cap grab the skin and apply a twisting motion to the patient""s skin. The twisting motion on the skin causes the puncture wound to bleed at a higher volume than if no twisting is applied. The twisting action is analogous to wringing a wet towel to force water from the fibers of the towel.
In addition, the alternate site cap also provides an advantage in that it is removable which allows the user to use the lancer as a conventional lancer when the conventional cap is attached.
Another feature of the present invention to enhance blood flow is provided by the new chisel point geometry of the lancet.
These and other aspects, features and advantages of the present invention, will become apparent from the following detailed description taken in conjunction with the accompanying drawings.